VTAM® deactivates sessions only when they are not currently assigned to a conversation and the number of sessions exceeds the negotiated session limits for the mode, and VTAM is responsible for deactivation. If session limits are lowered as the result of a CNOS negotiation, VTAM deactivates sessions to reach the lower session limits.

The negotiated draining value affects when sessions are deactivated. See Draining and session deactivation responsibility for more information on draining.

If the application program specifies ATTNLOSS=ALL on the APPL definition statement, VTAM schedules the ATTN(LOSS) exit when each session is deactivated. Otherwise, VTAM schedules the ATTN(LOSS) exit when the last session on the mode is deactivated.

VTAM returns the RPL6LAST field when the ATTN(LOSS) exit is scheduled. This provides information to the application program about the active sessions for the partner LU. RPL6LAST is found in the ISTRPL6 DSECT. The constant values for RPL6LAST are shown in Table 1.